Sleep enhances memories. It makes them stronger and more effective.

I found myself lying flat on my back in the middle of shop last weekend.  A robotic bed hummed and gently jiggled underneath me while I watched a presentation on a strategically placed screen just to the left of where I lay.  After 3 or 4 minutes of humming and jiggling, the computer spat out a report listing a range of mattresses that suited my individual sleep needs — $5839 for the best match.

Marketing ploy? Absolutely!  We haven’t handed over any money yet. But I was completely won over by the Sleep 101 presentation that was shown during my ‘mattress fitting’. They had the science of sleep pretty well spot on when they stated…

Sleep is essential to your body’s overall wellness, both physically and emotionally

But you know that, right?  I’m not going to dwell on the benefits of a good night’s sleep in this blog post, because we’re all very well aware of how terrible we feel without adequate sleep.

Instead, I’m going to focus on my other favourite sleep issue, one that I’m a passionate devotee of — the afternoon nap!

Professor Leon Lack, sleep scientist at Flinders University in Adelaide says,

A brief nap can not only reduce sleepiness but also improves cognitive functioning and psychomotor performance (the brain telling the body to move). A few minutes of shut-eye also considerably enhance short-term memory and mood.

A quick backgrounder in sleep …

Sleep is divided into two major phases of brain activity but named after eye-ball movement …

  • rapid-eye-movement (REM)
  • non–rapid-eye-movement (NREM) sleep.

When you first fall asleep you experience NREM sleep, and then 60 to 90 minutes later, REM sleep kicks in. During the course of a normal night, a healthy adult will experience 4 to 6 consecutive sleep cycles of REM and NREM.

When you’re in NREM sleep, your body is able to move, but your eyes don’t; your breathing  and heart rate slow and your blood pressure falls. Blood flow to the brain decreases, and electroencephalograms (EEGs – recordings of brain activity) show slowing of brain activity.

When you cycle into REM sleep, your body becomes immobile and yours eyes move about rapidly. Your blood pressure, heart rate, and breathing rate increase, and blood flow to the brain increases (and my gentlemen readers can attest to blood flow into other areas of the anatomy too). EEG activity also increases and you being to dream.

You also dream just as you enter NREM too.

Neuroscience has shown that …

NREM sleep is essential for learning and memory

Neuroscientists have been gathering evidence for some time that rats need NREM sleep to learn.  Patterns of electrical activity recorded from brain cells in the hippocampus (the brain structure involved in learning and memory) when rats explored a maze for the first time were repeated again in the hippocampus during post-learning sleep.

Scientists think that the maze memories become consolidated during NREM sleep.  Rats that were deprived of post-learning sleep were worse at finding their way through the maze compared to rats that slept.

This experiment has been repeated in humans.  People were invited to spend a day in the lab with Harvard sleep scientist Professor Robert Stickgold. They were trained to navigate their way through a virtual map at around lunchtime and then tucked up for a siesta immediately after.  Neuroscientists monitored their brain waves via EEG and woke them if they started to fall into REM sleep. A second group of maze navigators were left to sit quietly but not nap.

The people who napped performed much better than the non-nappers when they were retested at navigating the maze.

Professor Robert Stickgold says,

Sleep enhances memories.  It makes them stronger and more effective

My ongoing afternoon siesta research has taught me that the key to making the most of the afternoon nap is to keep it short. When I feel the mid-afternoon slump coming, I give in to it! I set my iphone for 30 minutes so I don’t fall into deeper sleep (and I assume without running my own EEG that I’m avoiding REM sleep), and I never wake feeling groggy. It might sound indulgent, but I like to apply neuroscience research to my daily life! So there you have it …

Boost your memory and mood by taking a short afternoon nap

 

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Do you ever indulge in an afternoon nap? Leave a comment below and tell me if you’ll be more likely to try to fit in a siesta after reading this post.

Brooks & Lack. 2006. A brief afternoon nap following nocturnal sleep restriction: which nap duration is most recuperative? Sleep. 29(6):831-40.  Wamsley, Tucker, Payne & Stickgold. A brief nap is beneficial for human route-learning: The role of navigation experience and EEG spectral power Learn Mem. 2010 July; 17(7): 332–336http://thesciencenetwork.org/programs/waking-up-to-sleep/robert-stickgold

16 Responses to The neurobiology of the afternoon nap

  1. I find 15 minutes is enough for me which means I have to set my iPhone for 16 minutes – cos it never takes me more than a minute to go to sleep anytime of day or night or anywhere for that matter. I know there are insomniacs everywhere who will hate me BUT I believe you can train yourself to go to sleep. And… the benefits of even 5 minutes “shut eye” cannot be overstated! Snooze on…

  2. I’m the same Sue – 2 minutes and I’m out for the count! It was interesting in the sleep store – they were saying that most people in buying a new bed report trouble sleeping. They said they rarely get someone in (like me) that says they sleep well!

  3. I’ve often needed a 15 minute recharge in the afternoon and working from home makes this easier for me. I know I can only have 15 minutes so my brain doesn’t let me fall into a deep sleep but the benefits of resting and relaxing into a light sleep is very beneficial.

  4. Thanks for the good read!
    I started taking naps when my babies were small. But I couldn’t afford to sleep long, because of grogginess. I trained my body to get up after 10 minutes. When I lay down, I go to my ‘sleep place’ … usually a beach somewhere. I feel the warmth of the sun, the gentle breeze, and the comfort of the sand. I’m usually immediately asleep!
    I try to take a 10 minute morning nap – usually around 9, and another nap around 3. I have tons of energy and typically sleep well at night. (though I usually only sleep 6 hours) I allow myself to wake on my own (no alarms) and get up immediately when I wake.
    This routine sure works well for me!

  5. Nice article, thank you! I read an article recently that neuroscientists have worked out that 26 minutes is optimal nap length between 1-3pm before hitting deep sleep. I enjoy a nanna nap when I can!

    Some enlightened companies have provided nap rooms to employees and they are always booked out eg: Huffington Post in New York (full article here http://sco.lt/99Aq2L).

  6. I typically take a 15 minute nap after lunch, maybe around 1, and then wake up and have my first cup of coffee for the day and a square of dark chocolate. It feels so indulgent, and in 20 minutes I am refreshed and ready to tackle the remainder of the day.

    • Sounds like my kind of perfect day! And there is some evidence showing that coffee prevents dementia. So drink up!

  7. Give the research supporting naps, I am surprised that many so called sleep experts still tell you it will ruin your night-time sleep. It would be nice if someone would reconcile the two.

  8. I had a brain Haeomorrhage 2 years ago and have leant that just sitting and being completely still or quiet for 30 minutes each day makes a massive difference to how I function. Early on in my recovery I used to have multiple naps during the day, but now I nap for 30 minutes every three or four days which is enough of a boost as long as I still get quiet time in between. If I don’t do this then my memory starts slipping, my balance falters and I can see the physical impact. So I am a convert to naps and down time as being a great way to rest the brain.

  9. Huge fan of the afternoon nap and get a great second wind in the evening! ….. am interested to know what the benefits of REM sleep are ….. my old learning was that REM was most important for learning ….. looking forward to seeing more ….. great article 🙂

  10. I learnt to deep relax when at university as part of a study on the effect of short deep relaxation on exam anxiety. Over the last 40 years or so, I have continued the practice and find a great beneficial effect on learning. When confronted with a new complex idea, I trust my brain to sort it out after feeding it as much relevant information as possible and then sleeping on it in the form of a short deep relaxation “nap”.

    I can also sleep anytime using the same techniques.

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